Pencil having a multicolored lead



Feb. 13', 1940. R. zur-KERT' PENCIL HAVING MULTICOLORED LEAD Original Filed pril l5, 1956 Scolors adjacent one another, and said ,colors Patented Feb. 13,

'PM-#ENTv OFFICE PENCIL HAVING A MULTICOLORED LEAD Richard Ziickert,

Budweis, Czechoslovakia, as-

signor to Koh-i-noor tuikrna L. & C. Hardtmuth, Budweis, Czechoslovakia, a irm original application April 1'5, 193s, serial No.

^ 74,470. Divided and this 1938, Serial No. 217,856

2 Claims.

I This invention relates to pencils having multicolored lead's by means whereof it is possible to write in a plurality of colors, so that the written stroke or mark as a rule exhibits at least two change rapidly.

This application is a division of my application Serial No. 74,470 filed April 15, 1936 now matured into Patent No. 2,165,827, July 11, 1939.

Processes are already known for the manufacture of two-colored or multi-colored leads, either by simultaneous extrusion froma nozzle having a plurality of` color channels vuniting in the said nozzleyor. by gluing together a plurality of' single-colored leads, or by assembling pieces of the color compositions, which in cross-section have the shape of circular sectors, so as to form a cylinder. This cylinder of color composition is then handled in the ordinary lead pencil extrusion press, having ordinary cylindrical containers for extruding the composition.

The fundamental disadvantages of these known processes is that when using the leads manufactured by them, the color changes much too infrequently, so that it is necessary to write much too long with the same color. The reason for this is that in all the processes, the possible number of color components in the lead is too small. In the last-mentioned known process, however, even with a large number of color components (in the factory it will scarcely be possible to join together properly more than'six sectors to form a cylinder), the boundary faces between two colors in the cylinder of color composition` and later in the lead, lie relatively close together only at the centreofthe shaft, while they diverge rapidly towards the periphery. As a pointed lead is used, vthe Writing point moves outwardly more and more from the centre of the shaft towards the periphery of the shaft, and the change in color will be more infrequent, so that the pencil marking is of the same color for a longer period.

A further disadvantage of the last-mentioned` sectional structure resides in the fact that the division of a cylindrical core into sectors and the re-assembling of differently colored sectors to form a new shaft or core, cannot be effected (on account of the blade-like shape of the sectors in the case of a large number of components) as accurately as to leave no air between the individual sectors. In extruding the composition from an extrusion nozzle, this air prevents an intimate 4union between the individual sectors. A lead produced in this way exhibits radially exapplication July 7,

(Cl. 1Z0-83) tending fissures which considerably impair its strength.

All these disadvantages are obviated by thel prfent invention. According to the invention,

a composition body, likewise composed of a plu- 5 rality of axially-directed components, 'each single colored in itself, is extruded through a single orifice, but the individual single-colored componentsv of the composition body have a square,

rectangular or other cross-section without acute 10 angles, which makes it possible to assemble and press the single-color components together during the extrusion process without any gaps, and to form acomposition body whichin cross-section has a checkered pattern in different colors.

A simple and therefore advantageous form of carrying out this process comprises extruding, by the normal manufacturing process used for making the shaft of a lead pencil, a numberof these rods into a'composite body or block having a 20 cross-section which is subdivided into many co1- ors in a checkered pattern, then introducing this composite body into a composition container of square' cross-section, and extruding said composite body from the container through a pref- 25 erably cylindrical extrusion' noz'zle, in order to form a cylindrical lead or shaft. I

The process according to the invention has first of all, the advantage that by means thereof,

it is possible to combine any desired large num- 30 'ber of components in the composite body, since the de-centralization in the cross-sectional dis-` tribution of the components renders the process independent of the number of such components.

There is, furthermore, the further advantage that 35 the individual components are very easy to manufacture, due to the fact that their cross-section is of simple shape, and their air-free assembly may also be carried out without any difficulty for the same reason. It is also 'possible to remove 40 the air from the assembled composition body by tapping and pressing it as by tapping its outer surface, so as to free it from the last residue of air whichvmay still be present, without the fear of thereby weakening the cohesion of the components.

Fig. 1 is an end View of a composite slug or cartridge which may be formed and extruded, ac-

cording to the invention. 5 Fig. 2 is a cross-section of a cylindrical pencil shaft which has been made by extruding the body illustrated in Fig. 1. Fig. 2 is drawn to enlarged scale.

To provide a numerical example, it is, for example, easily possible, according to the invention,

Cil

to use a composition container of square crosssections, the length of a side of this `crosssection being 80 mm. This container can be used with an extrusion nozzle, to press and to combine into a block, 64 lead rods, o f four different colors, for example, each rod having a. vsquare cross-sec-` tion, the length of a side of such cross-section being 10 mm. This is shown in Fig. 1. 1f this block is formed by extrusion into a cylindrical lead of 2.6 mm. diameter, the length of side of the squares of the checker pattern will be reduced in about 0.3 nim. Since the width of a written line is about 0.3 to 0.6 mm., the probability of the stroke being in two colors is very great even with this dimension. With these dimensions, 49 points of intersection of color boundaries are distributed over the interior of the cross-section of the lead, while the lead if subdivided in segment form only contains one such point of intersection. The length of side of the color composition components of square cross-section may be reduced still further without any difliculty, and the number of rods of different colors in one lead or shaft may be increased, thereby providing 'with certainty the probability that each stroke will consist of at least two colors.

The four different colors in Fig. 1 are indicated by difierent kinds of shading. v

As shown in Fig. 2 the completed shaft has a checkered pattern in cross-section, although the straight boundary lines in the original composite body have been distorted.

For the purpose of dening the invention in K the claims, it is noted that I extrude a slug or cartridge having elements of diii'erent colors so that the transverse cross-section of said slug or cartridge has a checkered pattern in which the elements of said composite sluggor cartridge are free .from acute angles. Likewise the elements of said composite slug or cartridge have longitudinal surfaces which substantially abut each other so that air spaces are eliminated when said composite slug or cartridge is extruded to make the shaft. I

I claim:

1. yA multi-colored cylindrical pencil shaft adapted for writing and drawing having a lplurality of friable longitudinal elements of different colors, said elements abutting each other along common longitudinal surfaces, the crosssections of said elements beingarranged in checkered pattern in the transverse cross-section of said shaft,.said cross-sections of said elements forming a composite cross-section having a plurality of individual element cross-sections in two directions squared one to the other.

2. A multi-colored cylindrical pencil shaft having a plurality of friable longitudinal elements of different colors, said elementsy abutting yeach lother along common longitudinal surfaces, the

cross-sections of said elements being arranged in checkered pattern in the transverse cross-section of said shaft, said cross-sections of said elements having greater dierences between their respective lengths and widths adjacent the periphery of said shaft, than adjacent the central part of said shaft.

RICHARD ZCKERT. 

